my red chickens have stopped laying all my legghorns still are why?

[roodude]

all my reds have stopped laying even my young ones the only ones still laying are my 6 legghorns and one rainbow layer i dont understand why i got them on a layer diet and have treated the for sickness which they have all seemed to gotten over with but daily egg count is still getting lower help

 

[chookhead]

Leghorns are a superior breed they lay and lay and lay and lay seriously they are amazing if they both eat the sane food and have been wormed etc etc then it only cones down to breed and age that's the only difference